• Title/Summary/Keyword: design forces

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Analysis of mechanical properties of agricultural products for development of a multipurpose vegetable cutting machine

  • Park, Jeong Gil;Jung, Hyun Mo;Kang, Bum Seok;Mun, Seong Kyu;Lee, Seung Hun;Lee, Seung Hyun
    • Korean Journal of Agricultural Science
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    • v.43 no.3
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    • pp.432-440
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    • 2016
  • The consumption of pre-treated vegetables (including fresh-cut vegetables) that are washed, peeled, and trimmed has been significantly increased because of their easy use for cooking. Vegetable cutting machines have been widely utilized for producing fresh-cut vegetables or agricultural products of different sizes; however, the design standard is not established for specific types of agricultural products. Therefore, this study was conducted to determine mechanical properties (compressive and shear forces) of targeted agricultural products (radish, carrot, squash, cucumber, shiitake mushroom, and sweet potato) for developing a multipurpose vegetable cutting machine. According to ASAE standard (s368.3), compressive and shear forces of targeted agricultural products were measured by using a custom built UTM (universal testing machine). Shape type of samples and speed ranges (5 - 15 mm/min) of loading rate on bioyield and shear points varied depending on the targeted agricultural product. The range of averaged bioyield points of targeted agricultural products were between 7.89 and 146.98 N. On the other hand, their averaged shear points ranged from 22.50 to 53.47 N. Results clearly showed that the bioyield and shear points of targeted agricultural products were thoroughly affected by their components. As measuring compressive and shear forces of a variety of agricultural products, it will be feasible to calculate blade cutting force for designing multipurpose vegetable cutting machine.

Human Body Mechanics of Pushing and Pulling: Analyzing the Factors of Task-related Strain on the Musculoskeletal System

  • Argubi-Wollesen, Andreas;Wollesen, Bettina;Leitner, Martin;Mattes, Klaus
    • Safety and Health at Work
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    • v.8 no.1
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    • pp.11-18
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    • 2017
  • The purpose of this review is to name and describe the important factors of musculoskeletal strain originating from pushing and pulling tasks such as cart handling that are commonly found in industrial contexts. A literature database search was performed using the research platform Web of Science. For a study to be included in this review differences in measured or calculated strain had to be investigated with regard to: (1) cart weight/ load; (2) handle position and design; (3) exerted forces; (4) handling task (push and pull); or (5) task experience. Thirteen studies met the inclusion criteria and proved to be of adequate methodological quality by the standards of the Alberta Heritage Foundation for Medical Research. External load or cart weight proved to be the most influential factor of strain. The ideal handle positions ranged from hip to shoulder height and were dependent on the strain factor that was focused on as well as the handling task. Furthermore, task experience and subsequently handling technique were also key to reducing strain. Workplace settings that regularly involve pushing and pulling should be checked for potential improvements with regards to lower weight of the loaded handling device, handle design, and good practice guidelines to further reduce musculoskeletal disease prevalence.

Influence of Malnutrition and Social Network on Health-related Quality of Life in Elders (노인의 영양위험과 사회망이 건강관련 삶의 질에 미치는 영향)

  • Kim, Hee Kyung;Chang, Hae Kyung;Lee, Mi-Ra;Son, Youn-Jung;Han, Su Jeong;Yang, Nam Young;Yoo, Myoung-Ran;Choi, Seon Young;Kim, Youn Mi
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.20 no.2
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    • pp.98-107
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    • 2013
  • Purpose: This study was done to identify the relationship of malnutrition, social network and health-related quality of life and to investigate the main factors influencing health-related quality of life in elders. Methods: The research design was a descriptive survey design using a convenience sampling. Data were collected by self-report questionnaires from 196 elders. Data analysis was done using SPSS 18.0 pc+ program for descriptive statistics, Pearson correlation coefficients and stepwise multiple regression. Results: The average score for health related quality of life was 3.33 (SD=0.86). Differences in health-related quality of life were statistically significant according to age, gender, occupation, presence of spouse, monthly income, source of income, economic status, medicine, and existence of chronic disease. Health-related quality of life was significantly correlated with malnutrition and social network. Major factors affecting health related quality of life for elders were malnutrition, occupation, age, social network, and economic status which explained 52.0% of the variance in health related quality of life. Conclusion: Findings provide a basis for developing nursing interventions to improve health-related quality of life. Future studies are needed a wide variety of variables that might influence health -related quality of life in elders.

Study on steel plate shear walls with diagonal stiffeners by cross brace-strip model

  • Yang, Yuqing;Mu, Zaigen;Zhu, Boli
    • Structural Engineering and Mechanics
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    • v.84 no.1
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    • pp.113-127
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    • 2022
  • Steel plate shear walls (SPSWs) are commonly utilized to provide lateral stiffness in high-rise structures. The simplified model is frequently used instead of the fine-scale model in the design of buildings with SPSWs. To predict the lateral strength of steel plate shear walls with diagonal stiffeners (DS-SPSWs), a simplified model is presented, namely the cross brace-strip model (CBSM). The bearing capacity and internal forces of columns for DS-SPSWs are calculated. In addition, a modification coefficient is introduced to account for the shear action of the thin plate. The feasibility of the CBSM is validated by comparing the numerical results with theoretical and experimental results. The numerical results from the CBSM and fine-scale model, which represent the bearing capacity of the DS-SPSW with varied stiffened plate dimensions, are in good accord with the theoretical values. The difference in bearing capacity between the CBSM and the fine-scale model is less than 1.35%. The errors of the bearing capacity from the CBSM are less than 5.67% when compared to the test results of the DS-SPSW. Furthermore, the shear and axial forces of CBSM agree with the results of the fine-scale model and theoretical analysis. As a result, the CBSM, which reflects the contribution of diagonal stiffeners to the lateral resistance of the SPSW as well as the effects on the shear and axial forces of the columns, can significantly improve the design accuracy and efficiency of buildings with DS-SPSWs.

Development and implementation of a knowledge based TBM tunnel segment lining design program (지식기반형 TBM 터널 세그먼트 라이닝 설계 프로그램의 개발 및 적용)

  • Jeong, Yong-Jun;Yoo, Chung-Sik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.16 no.3
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    • pp.321-339
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    • 2014
  • This paper concerns the development of a knowledge-based tunnel design system within the framework of artifical neural networks(ANNs). The system is aimed at expediting a routine tunnel design works such as computation of segment lining body forces and stability analysis of selected cross section. A number of sub-modules for computation of segment lining body forces and stability analysis were developed and implemented to the system. It is shown that the ANNs trained with the results of 3D numerical analyses can be generalized with a reasonable accuracy, and that the ANN based tunnel design concept is a robust tool for tunnel design optimization. The details of the system architecture and the ANNs development are discussed in this paper.

Determination of critical excitation in seismic analysis of structures

  • Kamgar, Reza;Rahgozar, Reza
    • Earthquakes and Structures
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    • v.9 no.4
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    • pp.875-891
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    • 2015
  • Earthquake can occur anywhere in the world and it is essential to design important members in special structures based on maximum possible forces that can be produced in them under severe earthquake. In addition, since the earthquake is an accidental phenomena and there are no similar earthquakes, therefore the possibility of strong earthquakes should be taken into account in earthquake-resistant design of important structures. Based on this viewpoint, finding the critical acceleration which maximizes internal forces is an essential factor in structural design. This paper proposes critical excitation method to compute the critical acceleration in design of important members in special structures. These critical accelerations are computed so that the columns' internal shear force at the base of the structure at each time step is maximized under constraints on ground motion. Among computed critical accelerations (of each time step), the one which produces maximum internal shear force is selected. A numerical example presents to show the efficiency of critical excitation method in determining the maximum internal shear force and base moment under variety of constraints. The results show that these method can be used to compute the resonant earthquake which have large enough effective duration of earthquake strong motion (between 12.86 sec to 13.38 sec) and produce the internal shear force and base moment for specific column greater than the same value for selected earthquakes in constructing the critical excitation (for different cases about 2.78 to 1.29 times the San Fernando earthquake). Therefore, a group of them can be utilized in developing the response spectrum for design of special structures.

Rational Sectional Force and Design Improvement of Abutment Wing-Wall (교대 날개벽의 합리적인 단면력 산정 및 설계 개선)

  • Chung, Wonseok;Kim, Minho;An, Zu-Og;Choi, Hyukjin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.31 no.3A
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    • pp.145-152
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    • 2011
  • Current Bridge Specification for Highway Bridges adopts a simplified method to determine sectional forces of abutment wing by dividing its area into four sections. This simplified method was developed in Japan when numerical analysis was not mature and computer resources were expensive. This simplified method has been with us without modification. This study evaluates the problem of current design practice to improve the design guideline for abutment wing. In this study, a finite element model of abutment wing based on shell elements was developed to obtain accurate sectional force. In addition, foreign design specifications regarding abutment wing were thoroughly examined. It has been observed that sectional forces obtained from the simplified method produce inaccurate results under various geometric shapes. Thus, it is recommended that two dimensional plate analyses should be adopted for future design of abutment wing wall.

Development of optimized TBM segmental lining design system (TBM 세그먼트 라이닝 최적 설계 시스템 개발)

  • Woo, Seungjoo;Chung, Eunmok;Yoo, Chungsik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.1
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    • pp.13-30
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    • 2016
  • This paper concerns the development of an optimized TBM segmental lining design system for a subsea tunnel. The subsea tunnel is normally laid down under the sea water and submarine ground which consists of soil or rock. The design system is the series of process which can predict segmental lining member forces by ANN (artificial neural network system), analyze suitable section for the designated ground, construction and tunnel conditions. Finally, this lining design system aims to be connected with a BIM system for designing the subsea tunnel automatically. The lining member forces are predicted based on the ANN which was calculated by a FEM (finite element analysis) and it helps designers determine its segmental lining dimension easily without any further FE calculations.

Conceptual Design and Analysis of Rotation-Aligning Bogie Mechanism for Inter-modal Automated Freight Transport Systems (인터모달 자동화물운송시스템을 위한 회전정렬형 대차의 개념설계 및 해석)

  • Ahn, Changsun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.4
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    • pp.632-638
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    • 2019
  • This paper presents the conceptual design and reaction force analysis of a bogie structure for an inter-modal automated transportation system, including road and rail transportation. The proposed system was based on a train with rotation-aligning bogie mechanism that can save significant time and cost. One of the critical issues in conceptual design is the lateral forces applied to the rail caused by the characteristic shapes and structure of the rails and bogie. In particular, the lateral forces are significant in the transition section between the driving and platform sections. This paper provides design guidance for the transition section through reaction force analysis. Based on the analysis result, it was confirmed that the proposed concept can be a valid design candidate of a practical system, and the radius of the rail and the distance between rails are major factors for reaction force generation.